Swaging mill roll



S. E.' DIESCHER SWAGING MILL ROLLE Filed March 25 1925 Z--Sheots-Sheet l 1W I/ENTUR July 5, 1927.

SWAGING Filed March 25, 1925 FIE-Z.

24 Z3 Z4 x 25 S. E. DIESCH ER MILL ROLL 2 Sheets-Sheet 2 WITNESSES /N VEN 70/? w prww.

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?atented July 5, 1%27.

U TATES WHEEL E. DIESCHEE, F PITTSBURGH, PENNSYLVANIA.

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Application filed March 25, 1925. Serial No. 18,258.

The invention concerns the construction of rolls used in the swa ing process of manufacturing seamless tu ing, accordin to which successive increments of a heate c pierced billet or work piece are intermittently fed to a pair of swaging rolls which are rotated in a direction opposite to that of the feeding movement of the work piece, and which, during each rotation, swage down an increment of the billet and finish a previously swaged increment, the billet being turned through an angle of 90 between each swaging operation of the rolls. The swaging is efi'ected by a bell-shaped portion or section of the roll pass, and the finishing by a uniform flared cylindrical portion of the pass which immediately adjoins the inner end of the bell.

To prevent undue wear upon the swa ing rolls, and hence to prolong their perioc s of efiectiveness, it is desirable to reduce to a minimum theslippage of work pieces upon the surfaces of the roll passes, and particularly upon the bell. Among other reasons,

such slippage results, in prior swaging mills,

from the manner of feeding work pieces at; 1the rolls, and from the shape of the The object of this invention is to provide 39 a pair of swaging rolls with a bell section so shaped that it will not, as an inherent consequence of its shape, slip upon work pieces being swaged.

The invention is diagrammatically illustrated in the accompanying drawings, of

which Fig. 1 is a transverse sectional view of a pair of swaging rolls, the plane of view being taken at the root of the roll pass,

and a longitudinal sectional view of a workpiece in the bite of the rolls and upon a mandrel; Fig. 2 a transverse sectional view of the finishing pass section of one of the rolls, the plane of view being taken at any point of such section, and being indicated generally by the line II-II, Fig. 1; and Fi 3 a transverse sectional view of the bel section of one of the rolls, illustrating how the location and extent of its working surface may be vdetermined, the plane of view being taken at any point of the bell, and bein indicated generally by the line III- IIL Fig. 1.

Having reference first to F1g. 1. a pair of swaging rolls 1 are shown as each being provided with a working pass comprising a hell or reducing section 2 and a finishing section 3 adjoinin it. The bell sectlon extends from about t e plane indicated at 4: to a plane indicated by a radial line 5 on a roll, and the finishing section extends from the latter plane to a plane clearly indicated at 6, and is ordinarily more than twice as long as the bell section. The shape of the working surface of bell section 2, and in which the present invention resides, Wlll presently be fully explained. The finishing section 3 is of cylindrical form, being flared at its sides. uniform throughout its extent,

and concentric with the axis of rotation 13 of the swaging roll. As far as concerns their general construction, the swaging rolls may be variously made either integrally or in sections, as is well known in the art.

In the operation of swaging mills of the type in which swaging rolls 1 are used, a heated pierced work piece 9 is carried oy a mandrel 7, which, between each swaging operation of the rolls and by movements of the mandrel, is intermittently fed longitudinally towards the rolls in the direction indicated bythe arrow 8 so as to progressively place unswaged increments of the billet in the bite of the swa ing bell of the rolls. The increments so to to the rolls may be uniform; or they ma vary, among other reasons, to compensate or the gradual cooling of a work piece. In addition to the intermittent longitudinal movement of the work piece for feeding it to the rolls, it is also turned angularly through an angle of 90 between each swaging operation.

As far as concerns the present invention, any desired or well known mechanism may be used for the longitudinal feeding and angular turning of the work piece. In all cases, however, as the swaging rolls operate upon a work piece to reduce an unswaged incrementof it and to finish a previously swa ed increment, provision is made in the fee mg mechanism for permitting the mandrel and work piece to move backwardly, that is to say in a direction opposite to that indicated by the arrow 8, while at the same time the mandrel exerts a feeding pressure upon the work iece to hold it in the grip of the rolls. T is backward movement of the work piece commences when the outer end of the bell strikes the work piece and continues as long as the working faces of the swaging rolls engage the work pieces.

To avoid slippage between the working surface of bell section 2 and the work piece, each bell section is, according to this invention, provided with a working surface which variably curves towards the center of the swaging roll from the beginning of the bell section, which is in the plane of radial plane 5, to the wide end of thebell. This inwardly curved surface is of such shape that its velocity components parallel to the axis of a work piece are the same for all points of such working surface as are simultaneously in contact with the work piece. For example, in Fig. 1 the wide end of the bell section 2 is shown in contact with work piece 9 from the point 4 to a point 10. The shape of the bell at and between these two points is such that at every instant during the rotation of the rolls all points on the working surface of the bell move parallel with the longitudinal axis of the work piece at the same velocity, and what is true of this particular section progressively applies to the entire working surface of the bell section as it progressively comes in contact with the work piece. The relation which here exists between the work piece and the shape of the working surface of the bell is similar to that between a rack and the face of a tooth of a pinion meshing with it.

While various curves may be used for shaping the working surface of the bell to attain the result explained, it is preferred to form an epicycloidal surface, commencing at the narrow end of the bell, in such a manner that the epicycloidal surface is tangent to finishing pass section 3 at their point of juncture, which oint is indicated b the radial plane 5. lthough the remain er of the surface may be generated by another curve, as for example an involute, it is preferred to form an epicycloidal surface throughout the entire extent of the bell.

In generating an epicycloidal surface, the epic cloid element at the root of the bell may be developed .by rotating a circle 11 on an are 12 whose center is the axis of rotation 13 of the swaging roll, circle 11 being of a diameter equal to the difference between theradius of curvature of'the root of finishing section 3 and the radius of are 12. The point of circle 11 used for developing the epicycloid forming the root of the pass is the point of tangency 14 of circle 11 with the are at the root of finishing section 3, which point of tangency lies11n'radial line 5. Other epicycloids used as elements for forming the e icycloidal surface may be similarly deve oped by rollin upon are 12 circles whose diameters are arger than that of circle 11 by an amount equal to the increased distance of the beginning of the epicycloid from axis 13. For example, an epicycloid element beginning at any assumed point 15 is developed by a circle whose diameter is the distance from point 15 to point 16, the latter bein the point of contact between developing circle 11 and are 12 in the position indicated. It will thus be seen that the epicycloidal surface is theoretically generated by an infinite number of epicycloidal lines each lying substantially in a plane perpendicular to the axis of the swaging-roll.

The radius of arc 12, which in turn determines the diameter of epicycloid developing circles such as circle 11, must be determined largely by experience, and varies for different size swaging rolls and for different conditions of operation incident, among other things, to the size of tube to'be manufactured and the size of the work piece. In general, the epicycloidal surface should be such that the mouth of the bell, indicated at 4, tends equally to compress the billet and press it rearwardly.

Because the work piece is, between each swaging operation, rotated through an arc of 90, the theoretical extent of the workin surface of the pass on each swaging r0 is 90. However, experience has shown that it is desirable to increase the extent of such working surface, for example to about 120,

leaving'a 60 flare at each side of the working surface. For the uniform finishing sec tion 3, this extent of the working surface, and the flare at its sides is shown in Fig. 2, in which circle 20 is of the diameter of the working surface of the finishing pass section. The finishingpass is here shown as exface of bell section 2 may be developed in the manner illustrated in Fig. 3 which is a typical cross-section of the bell section at any point throughout its extent, it being understood that the epicycloid elements of the surface must be spread laterally from i the root of the pass to effect the necessary flare of the bell. From this it follows that the epicycloidal lines on each side of the root of the pass do not lie precisely in planes perpendicular to the axis of the swaging roll, as has been previously indicatedQIn the first place, a. circle 26 is struck from the center line 25 of the pass, the radius of the circle being equal to the distance from line 25 to the epicycloid 27 at the root of the pass at the cross-section of the bell under consideration. To determine the position of the epicycloid which lies at the longitudinal edge of the working surface, a radial line 28 is laid out 60 from the vertical line 23, and its point of intersection 29 with circle 26 determined. A horizontal line 30 is then laid out representing the distance, from center line 25, of the epicycloid which is at the edge of the working surface of the pass, and a vertical line 31 is then dropped from point 29 to line 30. The point 32 where line 31 intersects line 30 determines the position of the outer edge of the epicycloidal surface at this section. In the manner explained with reference to the location of point 32, any intermediate point 36 of the epicycloidal surface may be located, the lines for determining the point '36 belng indicated at Fig. 3.

To detern iine the 'form of the flare surface of the roll adjoining the epicycloidal surface, a line '33 may be drawn tangent to circle 26 at the point of intersection of radial line 28 with it, and from the point 34- where line 33 intersects line 25, a line 35 may be drawn to point 32, which line defines the flare surface of the roll at the-section under consideration.

As will be understood by those skilled in-the art, the surface thus generated attains the stated object of this invention.

-All of its points which are simultaneously in contact with a work piece have, at each instance of the rotation of the rolls, the same velocity components parallel to' the horizontal axis of the work piece. Further- I more, the contour of the bell is progressively molded on the work piece. Hence there-is no slippage between the work piece and the working surface of the bell as an inherent consequence of the shape of such surface.

According to the rovisions of the patent statutes, I have exp ained the principle and extent of the workin operation of my invention, and have illustrated and described a manner of constructing it. However, I desire to have it understood that, within the scope of the appended claims, the invention maybe practiced by other forms of construction than that specifically shown and described. In particular, I desire to have it understood that the angular dimensions assumed in determining the surface and the flare at its edges are mere y typical and may be varied, and that in its broader aspects the invention is not limited to a bell having an epicycloidal working. surface.

I claim as mfy invention:

'1. A pair 0 rolls for swagin down a work piece fed longitudinally to t em, each roll having a portion of its face provided with a working pass commencing with a swaging bellsection and terminating with i swaging bell section and terminating with a uniform finishing section, the bell section being provided with a working surface tangent to said finishing section at its point of juncture with it and variably curving towardthe axis of rotation of the roll from said point of juncture to the other end of the bell, the velocity components parallel to the axis of the work piece being the same for all points of said working surface which simultaneously contact with the work piece.

3. A pair of rolls for swagin down a work piece fed'longitudinally to t em, each roll having a portion of its face provided with a working pass commencing with a swaging bell section and terminating with a uniform finishing section, the bell section being provided with a working surface tangent to said finishing section at its point of juncture with it and variably curving toward the axis of rotation of the roll from said point of juncture to the other end of the bell, said surface being epicycloidal from its juncture-with the finishing section and having its elements lying substantially in planes perpendicular to the axis of the roll, and the velocity components parallel to the axis of the work piece being the same for all points of said working surface which simultaneously contact with the work piece.

4. A pair of rolls for swaging down a work piece fed longitudinally to them, each roll having a portion of its face provided with a working pass" commencing with a swaging bell section and terminating with a uniform finishing section, the bell section being provided with an epicycloidal work ing surface, the elements of which lie substantially in planes perpendicular to the axis of the roll, said working surface being tangent to said finishing section at its point of juncture with it and curving toward the axis of rotation of the roll from said point SAMUEL E. DIESCHER. 

